Picking motion for looms



Nov. 16, 1954 s. o. DODGE PICKING MOTION FOR LOOMS 3 Sheets-Sheet 1 Filed April 17 1951 Nov. 16, 1954 s. o. DODGE PICKING MOTION FOR LOOMS 3 Sheets-Shet 2 Filed April 17, 1951 15204222202 fiwwood 0.Do

Nov. 16, 1954 s. o. DODGE 2,694,416

PICKING MOTION FOR LOOMS Filed April 17, 1951 3 Sheets-Sheet 3 afloolge,

PICKING MOTION FOR LOOMS Sherwood 0. Dodge, Medford, Mass., assignor to H. F. Livermore Corporation, Allston, Mass., a corporation of Delaware Application April 17, 1951, Serial No. 221,424

6 Claims. (Cl. 139-147) This invention relates to improvements in picking motions for looms and more particularly to improvements in the mounting of the pickershaft of such motions in change-box and other looms.

In the past when loom speeds were slower, shuttles were smaller and therefore lighter, pickersticks lighter, and the looms themselves are narrower, much less strain was placed on the pickershaft and its related parts and the consequent breakage thereof did not present an acute problem. However, in recent years, since loom speeds have increased and the picking load has become much heavier, frequent breakage of the rectangular section pickershaft has occurred as a result of the increased pressure of the pick-ball or roll upon the pick-cam and the greater resulting force transmitted to and through the pickershaft in looms employing this type of motion, so that the breakdown and resulting stoppage for replacement of the shaft have caused substantial losses of loom production time and repair costs. Little or no successful elfort has been directed toward overcoming such breakage of this pickershaft which in the usual Crompton & Knowles change-box loom runs from front to back of the loom and is supported on the loom side frames by bearings at its front and rear ends, the intermediate portions of the length of such shaft being of rectangular section as necessitated by the requirement of holding the pick-cam and the sweep-arm in fixed angular relation to the shaft and to each other under the violent and rapidly recurring pounding of the pick-ball which actuates the shaft and sweep-arm through its impact on the cam. In such looms, the shaft when at rest in its initial idle or starting position awaiting the stroke of the pick-ball rotating in a vertical plane has always been disposed with its flat top and bottom surfaces horizontal and its longer lateral surfaces vertical. Thus when the maximum thrust of the pick-ball against the pick-cam occurs at the limit of the throw or rotation of the pickershaft by the pick-cam, a rending force is concentrated at one edge of the pickershaft, i. e., at one corner of its rectangular section, which at this moment of maximum load has rotated into a position at the bottom of the shaft. This causes fatigue and cracking at this point, followed by progressive fracture and eventually complete breakage of the shaft usually at the point where it emerges from the forward end of the pick-cam body. Increasing the cross-sectional area of the pickershaft has proved no remedy, because the stiffening of this shaft diminishes its needed resiliency and increases the severity of the shock transmitted to its associated parts, causing breakage elsewhere.

It is the leading object of the present invention to prevent the occurrence of such breakage of the pickershaft under the thrust exerted by the pick-ball on the pick-cam, and especially under any degree of bending of the pickershaft during the described period of peak load.

I have discovered that the object of this invention can be attained by arranging the pickershaft in the best angular position about its axis to accept the inevitable bending thrust of the pick-ball. This is done by so changing the pick-cam and sweep-arm structures that at the moment at which the pick-ball has rocked the pickershaft on its axis to its full extent, the fiat under face of such shaft will be presented substantially at right angles to the maximum force of the thrust of the pickball, for example, with the bottom face horizontal in the common situation where this thrust is downward, whereby the rending or breaking strain on the pickershaft is distributed across the entire bottom face of the shaft. Such nited States Patent structure thereby avoids the concentration of the breaking strain at the corner of the pickershaft which occurs in prior structures as a result of having the maximum load fall on the pickershaft in the direction of the diagonal of its rectangular section.

An illustrative embodiment of the invention is shown in the accompanying drawings in which Fig. l is a perspective view showing the pickershaft and other parts connected with the pick motion at the lefthand side of a loom.

Fig. 2 is a perspective view from one side of the pickcam or shoe integral with a bracket for mounting it on the pickershaft.

Fig. 3 is an enlarged front elevation showing the relationship of the pickershaft, pick-cam and picking-ball before actuation of the pickershaft.

Fig. 4 is an enlarged front elevation showing the same parts as in Fig. 3 at the completion of the actuation of the pickershaft.

Fig. 5 is a side elevation showing a left-hand sweep arm and its means for attachment to the pickershaft.

Referring to the drawings, Fig. 1 shows the customary parts of the pick motion of a Crompton & Knowles loom, in which the cam-shaft 3 has keyed thereto the picking arm 5 which carries the picking-ball 7 rotating on adjustably mounted'stud 9. Extending transversely of and below the cam-shaft 3 is the pickershaft 11 of customary rectangular section as required to hold the pick-cam 13 and sweep arm 21 against angular rotation about the shaft under the powerful and rapidly repeated stresses to which they are subjected. The pick-cam 13 is of split hub type, of which the two portions are clamped around the picker shaft 11 by bolts 14 extending through holes 17, Fig. 2. The wing 19'of the pick-cam 13 extends about the axis of the shaft in an arc of about 45 As usual, since the pick-ball 7 first encounters the cam surface at the low end of the path 16, the center of the cam-shaft carrying the pick-ball 7 being above and forward of such point, the actual angular rotation imparted to the pickershaft is less than such arc, in common usage averageing around 25, as governed by the shape and proportions of the path 16 formed on the cam wing 19 and the proportions and relative locations of the cam shaft, picking arm and the mounting of the pick-ball 7 on its arm.

In accordance with the invention, the rectangular pickershaft 11 is installed in the hubs of pick-cam 13 and sweep arm 21, so that its bottom surface 30, Figs. 3 and 4, is at an angle D to the horizontal AB when in its waiting or starting position as in Fig. 3 with sweep arm 21 resting against its stop 29, tially equal to the angular distance through which the pickershaft has been rotated by the interaction of pickball 7 and cam 13, Fig. 4, when the pickershaft is subjected to maximum load, namely when the pick-ball is at the high point of the cam. Thus, when the angle C, Fig. 4, through which the pickershaft rotates is 25 in turning from its idle or waiting position of Fig. 3 to its position of maximum stress as indicated in Fig. 4, the angle D, Fig. 3, will likewise be made 25. Otherwise stated, the waiting or idle angle of the bottom (or top) face of pickershaft 11 is set back or given a lead from its conventional prior horizontal starting position equivalent to the amount of angular throw imparted to the pickershaft by the pick-cam. Commonly the bottom face 30 will be substantially horizontal at this moment of maximum stress, as shown in Fig. 4, since the resistance of the sweep arm and the parts actuated thereby apparently converts the main portion of the force of the pick-balls blow as delivered to the pickershaft into a component directed vertically downward.

This inclined starting position of the faces of the pickershaft is attained by appropriate angular orientation of the passage 32 through the split hub 34 of the pick-cam 13, and of the passage 36 through the hub 38 of sweep arm 21, which latter member determines the starting position of the pickershaft through engagement with stop 29 on the loom side.

As will be plain from the foregoing, the horizontal radius lying in plane AB of Fig. 3 in moving to A'--B' in Fig. 4 defines the angle through which pickershaft 11 moves from its waiting position of Fig. 3 as the pickthis angle being substanball travels from its initial point of contact to the conclusion of its engagement with cam surface 16 at the high point of the cam, arrival at such high point being the moment at which the pickershaft is under maximum stress, and the moment when it is desired to have the bottom face of the shaft at right angles to the main component of thrust delivered by the pick-ball, or horizontal in the example illustrated, wherein the pick-ball travels in a path lying in a vertical plane. Thus whereas the inevitable bending of the shaft under impact of the pick-ball previously occurred in the plane of the diagonal of the shafts section to stretch most severely the bottom edge of the shaft which edge previously lay at the outermost part of the curve resulting from bending, now the whole width of the bottom face is disposed on the outside of the bend, and at a shorter radius, and the strain finds no salient edge in which to concentrate and reach a maximum to cause fracture and eventual breakage of the shaft. Instead, the strain is distributed across. the entire width of thfe bottom face of the pickershaft, greatly increasing its li e.

While reference has been made to a throw of the pickershaft of 25, it will be understood that the practice of my invention is not limited to any such angle, but that however great or small the throw may be, the starting-point of the shaft will be made such that its bottom surface will be perpendicular to the main transverse component of stress at the instant of maximum load.

While I have illustrated and described a certain form in which the invention may be embodied, I am aware that many modifications may be made therein by any person skilled in the art, without departing from the scope of the invention as expressed in the claims. Therefore, I do not wish to be limited to the particular form shown, or to the details of construction thereof, but what I do claim is:

1. A picking motion for a loom having in combination a cam shaft, a picking arm, a pick-ball, a rectangular pickershaft, and a pick cam body portion having surfaces to engage the pick-ball, such cam surfaces being so angularly disposed about the axis of the pickershaft that a face of such shaft is in a plane at right angles to the plane of rotation of the pick-ball when the latter is at the high point of the cam.

2. A picking motion for a loom having in combination a cam shaft, a picking arm, a pick-ball, a rectangular pickershaft, and a pick cam body portion having surfaces to engage the pick-ball, such cam surfaces being so angularly disposed about the axis of the pickershaft that a bottom face of such shaft is in a horizontal plane at right angles to the plane of the path of travel of the pick-ball when the latter is at the high point of the cam.

3. A picking motion for a loom having a cam shaft with a picking arm and ball, and having a rectangular pickershaft, a pick cam body portion having surfaces to be engaged by the pick-ball, such cam portion being so angular disposed about the axis of the pickershaft that at the conclusion of the engagement of the pick-ball with such cam surface the bottom face of the pickershaft is at substantially right angles to the plane of the path of travel of the pick-ball.

4. A picking motion for a loom having in combination a cam shaft, a picking arm, a pick-ball, a rectangular pickershaft, and a pick cam engaged by the pick-ball, the pickershaft when at rest being disposed with two of its faces in planes at an angle to the plane of rotation of the pick-ball substantially equalling the actual amount of the throw imparted thereto by engagement of its cam with the pick-ball whereby the stretching strain produced by the bending of the pickershaft under the action of the pick-ball is distributed evenly across the bottom face of such shaft..

5. In a picking motion for a loom having a cam shaft, a picking arm, a pick-ball, a rectangular pickershaft, and a pick cam engaged by the pick-ball, the pickershaft when in its .idle position having its bottom surface in a plane at an angle to the horizontal equal to the actual amount of the throw imparted thereto by engagement of the cam with its pick-ball, whereby the bottom surface is disposed in horizontal relation and in a plane at right angles to the downward thrust of the pick-ball substantially at the instant when such thrust reaches its maximum.

6. In a picking motion for a loom having a cam shaft, a picking arm, a pick-ball, a rectangular pickershaft, and a pick cam engaged by the pick-ball, the pickershaft when in its idle position having its bottom surface in a plane at an angle to the horizontal equal to the actual amount of the throw imparted thereto by engagement of its cam with the pick-ball, the pickershaft at the conclusion of the engagement of the pick-ball with such cam surface having its bottom surface horizontal and in a plane at right angles to the plane of rotation of the pick-ball.

References Cited in the file of this patent UNITED STATES PATENTS Nault Dec. 31, 1946 

